Prior to the present invention, phenolic imine compounds were prepared by the so-called Gibbs Reaction. H. D. Gibbs, Chem. Review 13, 291-319 (1927). See also D. Svobodova, et al., Mikrochimica Acta, pp. 251-264 (1978). These references, the contents of which are incorporated herein by reference, describe the coupling of phenols with imines in accordance with ##STR4##
Such reactions are useful in a test for determining the presence phenols.
The novel compound of the present invention is not only useful as a reporter substance for detecting ions in a test sample, but provide stability during storage and is relatively free from interfering side reactions in a sample.